Let's discuss cam bearings

I am almost to the point of having enough cash to get my 464 block ready to assemble. I still need a cam as well as cam bearings yet. Been looking at the TA 1559 coated cam bearings as I am thinking of going with a roller camshaft(if they ever become available again). If things don't work out with a roller cam,are these cam bearings overkill in the motor,or just extra insurance? Going with the TA Stage 2 heads as well.Trying to decide on a camshaft that will work with my combo too...Cam suggestions??

 

I put them in my new build, cheap insurance really so it's a no brainer.

 

You will never be sorry you did use them and you may be sorry if ya don't.

 

Here's the deal with cam bearings.

1. The design of our engines puts all the oil for the LH lifter galley, in a groove on the front Journal of the cam... What happens is, the cam wears into the bearing, and starts to slowly restrict the oil supply to the left hand lifter valley. and slowly you start to develop lifter noise on the driver side bank, and wear in the rocker gear due to lack of oil.

Really common to see high mileage stock cores that you have to pry the cam out of .. because they are locked in place by that groove worn into the bearing.

2. Our other issue is excessive bearing wear, due to high spring pressures. The issue here is where the oil is introduced into the bearing.

Picture the front of the engine, and superimpose a clock on the camshaft. The oil is introduced at 9am... and has to travel all the way around the cam/bearing interface to get to the high load areas at 6pm... and since at 12 o'clock we have all the journal/bearing clearance, volume and pressure tend to bleed off at that point. Even if we have the ideal .0015 cam journal to bearing clearance, because the cam is being pushed down by the valve springs, all that clearance is at the top.. and in the real world, it's often more like twice that number.

Before the TA Bearings came out, the fix was to take a die grinder to the front journal and make a groove from where the oil comes into the journal at 9"oclock, around the top to the oil hole that goes to the LH galley.. And then put the bearing in upside down, to get the oil into the front journal about about 1 pm.. This solved the drying out of the LH galley, and got the oil in at a better place.

And then some would go into the other 4 journals, and perform the same operation, putting a groove in the bearing journal in the block, from 9am to 1pm or so.. and then installing the bearings with the oil hole at 1pm or so.

The TA bearings solved both of these issues, by redirecting the oil path and introduction position. And they only cost about $20 more than the BP-9 Durabond bearing.

The B-9 standard bearing is fine in a pure stock rebuild, with less than 230 lbs of open valve spring pressure. It has no place in a performance engine.

I use the TA 1559A cam bearing set in every performance engine built here, as long as they are available.. when they aren't, then I will use just the front TA bearing (I always keep a set stashed for when TA runs out) and then use the Durabond Performance bearing in the 4 rear positions. And honestly, with any hydraulic flat tappet cam, that probably is just fine.. it's only when you get considerably over 300 lbs of open spring pressure, that the wear issues really show up on bearings 2-5.

The roller cam cores did not have the groove in the front journal, so they must be installed with the TA bearing, or with a modified block.

I don't use the Teflon coated TA bearings. The coating on the bottoms wears off very quickly, and they are coated on top of the normal ID bearing.. which reduces the cam-bearing clearance to the point that they don't "spin right" when installed.

The "spin test" is very important when installing your cam.. after the bearings are installed, with just a little light oil on the bearings/journals the cam is installed and tested to for fit. It should turn very easily with just the tips of your fingers. This insures two things.. the cam bearings are correctly installed, and the cam is not bent.

You can't get that feel with the coated bearings, they always turn like crap.

So I stay away from the Teflon coated ones.

JW

 

I love the TA 608B hydraulic cam designed for Stage 2.

 

I was out in the garage looking at my parts that I have for this motor I have accumulated. I am happy to say I have 2 sets of the TA 1559A cam bearing sets.Looks like I have to run the block to Jersey and get some things done on this motor and then I can get it assembled. Maybe this beater will make it out of the garage next summer afterall..

 

Jim, Try calico coatings. Big difference!

 

If the day comes when I need to deal with a cam bearing issue, I will certainly do that.

JW

 

Jim,

Quicky question. Since a NailHead crank can be installed in a 455 could the cam bores & lifter bores be trued up like you do for the 455's???
Since the Nail is HP deficient adding 20HP to the total numbers would be a plus.
Just a thought.

Tom T.

 

I asked Ron what he thought... he said it is very unlikely that the spacing is the same between the two engines.. I know for sure the deck height and cam to crank C/L is different. He doubted he could do it without creating a new fixture setup.

The other issue is that you have to come up with a cam bearing, with the same ID as the stock bearing, but a oversized OD, to allow for boring to straighten the cam tunnel. Their might be something out there, you would have to investigate a durabond cam bearing catalog.

JW

 

Jim,

I do know a few guys that have run a "Nail" crank in their 455's to get a forged crank on the cheap. Seems to me bore spacing would be the same??? The "Nails" cam bearings get smaller as they progress to the rear.
So enlarging the four is not a big deal. Just have to find bearings that are a suitable size. Larger lifter bores shouldn't be a problem.
These are only my thoughts.

Tom T.

 

Tom,
The spacing he is talking about is crank to cam center-line, crank to deck height, cam center-line to deck, and lifter bore to lifter bore center-line.

I don't believe any of those are the same as the later BBB.

The cam tunnel and BHJ Lifter tru tooling are designed around those datum points.

JW

 

JW. Thanks for posting.
Only issue I have is it can hear slight valve train noise only at idle on drivers side.
First it was both sides with the lifters TA supplied with the 413 cam. I thought those might have been a Rodes lifter? Then I changed to Johnson lifters and pasanger side was Quiet at idle. call it mechanics ear. But.
I can still hear slight noise on drivers side, across valve train at idle.. Most spectators dont say anything about it except. Sounds great. But I can heard it and a few friends once I point it out.
I've studied the design of the back groves bearing. I have oil and pressure to drivers side. But I believe not enough volume at idle.
I've thought about grooving the front cam bore. Or T ing of the oil sender to the drivers rear oil galley plug with a steel line.
My thought its the duel groves and offset oil holes can't deliver the volumn at idle. 750 Rpm. At 190*
Oil pressure was 28 to 30 PSI..
Brad Pen 10-40.
I figured this was a great opertunity to ask you if you have seen and herd this irritating issue?
Also. What's your recomend fix to get more oil to drivers side lifters?
Rich...

 

You could run a feed line from oil sending spot to driver's side rear cam plug.
Only problem with that is that if you eat front cam bearing you won't know it.

 

Yes Larry with the hood open. Just drivers side. Passinger side quiet.
Just woundered if the back groved cam bearing reclocked allowed enough oil volume to pass.
Thanks for the link

 

I was going to mention the same thing as JW said about the Teflon coating, don’t bother spending the money on the coating, the journals aren’t suppose to touch the bearings anyway. DO buy the back grooved bearings

 

There are coatings (not teflon) that are thin and add little or nothing to clearance. Good insurance especially on the front one which sees alot of load from timing chain, distributor and oil pump. In ideal world no there should be no contact but look at one after alot of miles. I've seen the front one in pretty bad shape and all the others perfect.